The overall research objectives are to determine the role of hemodynamic factors in the physiology of the pulp and gingiva in health and disease. Macrocirclulatory methods will be applied with the aim of characterizing hemodynamics of the normal and pathologically altered pulp and gingiva at the organ level, and microcirculatory functions at the local level. Macrocirculatory measurements of blood flow will be made by both the Xe-133 Washout and the Microsphere methods in dogs. Microcirculatory studies will be conducted in the rodent pulp and in the canine gingiva with microscopic determination of the following parameters in single unbranched microvessels in the microvascular network. These include the red cell velocity by the "two slit" photometric technique, the distribution of volumetric flow and vascular pattern. Capillary permeability of the pulp and gingiva following various interventions will be assessed by fluorescence vital microscope. Corrosion resin vascular casts of the pathologically altered pulp and gingiva will be examined under a S.E.M. The effects of electrical stimulation of the cervical sympathetic nerve, various humoral interventions, changes of rheological parameters and oxygen transport, and experimentally induced hypotension on macro- and microcirculatory hemodynamics will be determined. The micro-/macrocirculatory findings under various perturbations will be correlated. Furthermore, the macrocirculatory methods will allow an assessment of hemodynamic contributions to the pulp-gingiva (i.e., endoperio) relationship in health and sisease states. This project, by using well established methods of inducing inflammation in the pulp and gingiva and newly developed macro- and microcirculatory techniques will allow the systematic evaluation of the role of hemodynamic factors in the physiology of the pulp and gingiva in health and disease.